Quantum circuit simulation is crucial for quantum computing such as validating quantum algorithms. We present Qymera, a system that repurposes relational database management systems (RDBMSs) for simulation by translating circuits into SQL queries, allowing quantum operations to run natively within an RDBMS. Qymera supports a wide range of quantum circuits, offering a graphical circuit builder and code-based interfaces to input circuits. With a benchmarking framework, Qymera facilitates comparison of RDBMS-based simulation against state-of-the-art simulation methods. Our demonstration showcases Qymera's end-to-end SQL-based execution, seamless integration with classical workflows, and its utility for development, benchmarking, and education in quantum computing and data management. A video demonstrating Qymera's key features can be found at https://youtu.be/j-fTKnVIV6c.